Numerous previous patent applications by the inventors have documented important therapeutic actions of the n-6 and n-3 essential fatty acids. These essential fatty acids (EFAs) and their bodily conversion pathways are set out in Table 1 below.
TABLE 1 __________________________________________________________________________ n-6 EFA's n-3 EFA's __________________________________________________________________________ 18:2n-6 18:3n-3 Linoleic acid, LA) (.alpha.-Linolenic acid, ALA) .dwnarw. .delta.-6-desaturation .dwnarw. 18:3n-6 18:4n-3 (.gamma.-Linolenic acid, GLA) (Stearidonic acid) .dwnarw. elongation .dwnarw. 20:3n-6 20:4n-3 (Dihomo-.gamma.-linolenic acid, DGLA) .dwnarw. .delta.-5-desaturation .dwnarw. 20:4n-6 20:5n-6 (Arachidonic acid, AA) (Eicosapentaenoic acid, EPA) .dwnarw. elongation .dwnarw. 22:4n-6 22:5n-3 (Adrenic acid) .dwnarw. .delta.-4-desaturation .dwnarw. 22:5n-6 22:6n-3 (Docosahexaenoic acid, DHA) __________________________________________________________________________
The acids, which in nature are of the all-cis configuration, are systematically named as derivatives of the corresponding octadecanoic, eicosanoic or docosanoic acids, e.g. z,z octadeca-9,12-dienoic acid or z,z,z,z,z,z docosa-4,7,10,13,16,19-hexaenoic acid, but numerical designations based on the number of carbon atoms, the number of centres of unsaturation and the number of carbon atoms from the end of the chain to where the unsaturation begins, such as, correspondingly, 18:2n-6 or 22:6n-3, are convenient. Initials, e.g. EPA and shortened forms of the name e.g. eicosapentaenoic acid are used as trivial names in some of the cases.
The preferred fatty acids of the present invention are the ten n-6 and n-3 essential fatty acids that are beyond the 6-desaturation step, desirably in all -cis form, but the invention is not limited to them nor to acids in which the chain contains repeating --CH.dbd.CH--CH.sub.2 -- units. Columbinic acid and .alpha.-parinaric acids, for example, are also suitable, being e,z,z-octadeca-5,9,12-trienoic acid and z,e,e,z-octadeca-9,11,13,15-tetraenoic acid, respectively.
The therapeutic actions include desirable effects in many different diseases including cardiovascular diseases, diabetes, skin diseases, inflammatory diseases and immunological diseases, cancer, psychiatric disorders, renal diseases, prostatic disorders and gastrointestinal and other diseases.
By their nature, EFAs are highly hydrophobic compounds which are soluble in water to a negligible extent. However, there are many reasons why it would be desirable to have a water soluble form of these compounds. Such water soluble derivatives may, for example be more easily absorbed from the gut via the hepatic portal system; may be given intravenously with ease; and may be used in many other ways such as in topical formulations, formulations for local administration, innovative oral formulations including drinks, enteral foods, and skin care preparations including lotions, shampoos, creams and so on.
Meglumine (N-methyl glucamine, an N-alkyl polyhydroxy amine) is an agent which is widely used in pharmaceutical formulations and which has an excellent safety profile. The formula is: ##STR1##
We have found that the meglumine derivatives of EFAs are highly water soluble and can therefore be used in many different ways in the formulation of pharmaceuticals, foods, nutritional supplements, skin care products and drinks of many different sorts. The invention can also be applied to a wide variety of other polyunsaturated fatty acids, other than those belonging to the n-6 and n-3 series, which have 16 to 26 carbon atoms, up to 6 double bonds, and with the double bonds in either the cis or trans configuration.